JP2016507910A - Video decoder using signaling - Google Patents

Abstract

A method of decoding a video bitstream, receiving reference picture set parameters from the video bitstream; decoding a current picture using inter prediction based on the reference picture set; Storing the decoded picture referenced for decoding in a decoded picture buffer, wherein the reference picture set selects at least (a) the least significant bit (LSB) of the picture order count (POC) of the reference picture Decoded by using one or more reference picture identifiers based on each of the number of received pictures; and (b) a flag that specifies whether there is subsequent data that determines the MSB of the POC of the reference picture Subsequent data has the following condition (i): Sub-trailing trailing picture with 0 TemporalId value after the picture satisfying condition (i), and (ii) the remainder satisfying condition (i) Or a method that exists for a picture that satisfies one of the following pictures in decoding order, including a reference picture up to the first picture in decoding order.

Description

Cross-reference of related applications None.

  The present invention relates to video encoding and / or decoding.

  Digital video is typically represented as a series of images or frames, each containing an array of pixels. Each pixel includes information such as luminance and / or color information. In many cases, each pixel is represented as a set of three colors, and each color can be defined with an 8-bit color value.

  For example, H.C. Video coding techniques such as H.264 / MPEG-4 AVC (H.264 / AVC) typically provide higher coding efficiency at the expense of increased complexity. Increasing image quality requirements and image resolution requirements for video encoding techniques also increase the complexity of encoding. A video decoder suitable for parallel decoding can improve the speed of the decoding process and reduce memory requirements, and a video encoder suitable for parallel coding improves the speed of the encoding process and reduces memory requirements be able to.

  Each of which is incorporated herein by reference in its entirety. H.264 / MPEG-4AVC [joint video team of ITU-T VCEG and ISO / IEC MPEG, “H.264: Advanced video coding for generic audios” ITU-T Rec. H. H.264 and ISO / IEC 14496-10 (MPEG4-Part10), November 2007], and similarly, JCT-VC, ["Draft Test Model Under Consideration", JCTVC-A205, JCT- VC Meeting, Dresden, April 2010 (JCT-VC)] is a video codec (encoder / decoder) specification that decodes pictures based on reference pictures in a video sequence for compression efficiency.

  The above and other objects, features and advantages of the present invention will be more readily understood when the following detailed description of the invention is considered in conjunction with the accompanying drawings.

  One embodiment of the present invention is a method of decoding a video bitstream, receiving a reference picture set parameter from the video bitstream; decoding a current picture using inter prediction based on the reference picture set Storing the decoded picture referenced for future inter prediction in a decoded picture buffer, the reference picture set comprising at least (a) a picture order count (POC) of a reference picture; one or more reference picture identifiers each based on a selected number of least significant bits (LSB) of picture order count (LSB); and (b) subsequent data determining the MSB of the POC of the reference picture Whether finger And the subsequent data has more than one reference picture with the remainder of dividing the picture order count by MaxPicOrderCntLsb in the decoded picture buffer equal to PocLsbLt: (Ii) After the picture satisfying the condition (i), the temporalId value is 0, and the trailing picture or reference picture of the substream, including the first picture in the decoding order and subsequent pictures in the decoding order Disclose methods that exist for pictures that satisfy one of them.

H. 2 is a diagram illustrating a H.264 / AVC video encoder. FIG. H. 2 is a diagram illustrating a H.264 / AVC video decoder. FIG. FIG. 3 shows an exemplary slice structure. FIG. 5 illustrates another exemplary slice structure. It is the figure which showed reconstruction of the entropy slice. FIG. 6 is a diagram illustrating reconstruction of a part of the entropy slice of FIG. 5. It is the figure which showed reconstruction of the entropy slice using the abbreviated LSB count value. It is the figure which showed reconstruction of the entropy slice using a long-term picture value. FIG. 6 is a diagram illustrating restructuring of an entropy slice by selecting a first preceding frame using a long-term picture value. FIG. 5 shows the reconstruction of entropy slices by using overlapping long-term picture frames having the same least significant bit count value. It is the figure which showed the technique for selecting a reference frame. It is the figure which showed the technique for selecting a reference frame. FIG. 6 shows another technique for selecting a reference frame. FIG. 6 shows another technique for selecting a reference frame. FIG. 6 shows another technique for selecting a reference frame. FIG. 6 shows another technique for selecting a reference frame. It is the figure which showed the picture in which delta_poc_msb_present_flag [i] is set to 1.

  Although the embodiments described herein may correspond to any video coder / decoder (codec) that uses encoding / decoding, the exemplary embodiments are described in H.264 only for illustrative purposes. H.264 / AVC encoder and H.264 The H.264 / AVC decoder will be described. Many video coding techniques are based on a block-based hybrid video coding approach, and source coding techniques involve inter-picture prediction that can be considered between frames, intra-picture prediction that can be considered as intra-frame, and transformation of prediction residuals. It is a hybrid of encoding. Interframe prediction can use temporal redundancy, and intraframe and transform residual prediction coding can use spatial redundancy.

  FIG. 1 is a block diagram illustrating an exemplary encoder 104 of electronic device 102. It should be noted that one or more of the elements shown as included in the electronic device 102 may be implemented in hardware and / or software. For example, the electronic device 102 includes an encoder 104, which may be implemented in hardware and / or software.

  The electronic device 102 may include a supplier 134. The supplier 134 can supply picture or image data (eg, video) as the source 106 to the encoder 104. Non-limiting examples of the supplier 134 include an image sensor, memory, communication interface, network interface, wireless receiver, port, video frame content, previously encoded video content, unencoded video content, etc. Is included.

  Source 106 may be provided to an intra-frame prediction module and reconstruction buffer 140. Source 106 may also be provided to motion estimation and motion compensation module 166 and also to subtraction module 146.

  Intraframe prediction module and reconstruction buffer 140 may generate intra mode information 148 and intra signal 142 based on source 106 and reconstruction data 180. Motion estimation and motion compensation module 166 may generate inter-mode information 168 and inter signal 144 based on source 106 and signal 198 in reference picture buffer 196.

  The signal 198 in the reference picture buffer 196 may include data from one or more reference pictures stored in the reference picture buffer 196. Reference picture buffer 196 may also include an RPS index initialization module 108. The initialization module 108 may process reference pictures corresponding to RPS buffering and list construction.

  The encoder 104 can select between the intra signal 142 and the inter signal 144 according to the mode. Intra signal 142 can be used to take advantage of spatial features in a picture in intra coding mode. The inter signal 144 can be used to take advantage of temporal features between pictures in the inter coding mode. On the other hand, in the intra coding mode, the intra signal 142 may be supplied to the subtraction module 146 and the intra mode information 158 may be supplied to the entropy coding module 160. On the other hand, in the inter coding mode, the inter signal 144 may be supplied to the subtraction module 146 and the inter mode information 168 may be supplied to the entropy coding module 160.

  To generate the prediction residual 148, either the intra signal 142 or the inter signal 144 is subtracted from the source 106 (depending on the mode) at the subtraction module 146. The prediction residual 148 is supplied to the conversion module 150. The transform module 150 can compress the prediction residual 148 to generate a transformed signal 152 that is provided to the quantization module 154. The quantization module 154 quantizes the transformed signal 152 to generate a transformed and quantized coefficient (TQC) 156.

  The TQC 156 is supplied to the entropy encoding module 160 and the inverse quantization module 170. The inverse quantization module 170 performs inverse quantization on the TQC 156 to generate an inverse quantization signal 172 supplied to the inverse transform module 174. The inverse transform module 174 decompresses the inverse quantized signal 172 to generate a decompressed signal 176 that is supplied to the reconstruction module 178.

  The reconstruction module 178 can generate the reconstruction data 180 based on the decompressed signal 176. For example, the reconstruction module 178 can reconstruct a (modified) picture. Reconstruction data 180 may be provided to deblocking filter 182 and to intra prediction module and reconstruction buffer 140. Deblocking filter 182 may generate filtered signal 184 based on reconstruction data 180.

  The filtered signal 184 may be provided to a sample adaptive offset (SAO) module 186. The SAO module 186 may generate SAO information 188 that is supplied to the entropy encoding module 160 and a SAO signal 190 that is supplied to an adaptive loop filter (ALF) 192. The ALF 192 generates an ALF signal 194 that is supplied to the reference picture buffer 196. The ALF signal 194 may include data from one or more pictures that can be used as reference pictures.

  Entropy encoding module 160 may encode TQC 156 to generate bitstream 114. The entropy coding module 160 uses context-adaptive variable length coding (CAVLC) or context-adaptive binary arithmetic coding (CABAC) using context-adaptive binary arithmetic coding (CBAC15). Can be encoded. In particular, entropy encoding module 160 may encode TQC 156 based on one or more of intra mode information 158, inter mode information 168, and SAO information 188. The bitstream 114 can include encoded picture data. Encoders often encode frames as a sequence of blocks, commonly referred to as macroblocks.

  Quantization associated with video compression, such as HEVC, is a lossy compression technique that is achieved by compressing a range of values into a single value. A quantization parameter (QP) is a predetermined scaling parameter used to perform quantization based on both the quality of the reconstructed video and the compression rate. A block type is defined to represent the characteristics of a given block in HEVC based on block size and its color information. The QP, resolution information, and block type may be determined before entropy coding. For example, the electronic device 102 (eg, the encoder 104) may determine the QP, resolution information, and block type, and these may be supplied to the entropy encoding module 160.

  Entropy encoding module 160 may determine the block size based on the block of TQC 156. For example, the block size may be the number of TQC 156 along a one-dimensional TQC block. In other words, the number of TQC 156 in the block of TQC may be equal to the square of the block size. For example, the block size may be determined as the square root of the number of TQC 156 in the block of TQC. Resolution can be defined as pixel width x pixel height. The resolution information can include picture width, picture height, or the number of pixels of both. Block size can be defined as the number of TQCs 156 along a 2D block of one-dimensional TQC.

  In some configurations, the bitstream 114 may be transmitted to another electronic device. For example, the bit stream 114 may be supplied to a communication interface, a network interface, a wireless transmitter, a port, and the like. For example, the bit stream 114 may be transmitted to another electronic device via a LAN, the Internet, a mobile phone base station, or the like. The bitstream 114 may additionally or alternatively be stored in the memory of the electronic device 102 or other electronic device.

  FIG. 2 is a block diagram illustrating an exemplary decoder 212 on the electronic device 202. The decoder 212 may be included in the electronic device 202. For example, the decoder 212 may be a HEVC decoder. Decoder 212 and / or one or more of the elements illustrated as included in decoder 212 may be implemented in hardware and / or software. Decoder 212 may receive bitstream 214 (eg, one or more encoded pictures included in bitstream 214) for decoding. In some configurations, the received bitstream 214 may include reception overhead information such as a received slice header, received PPS, and received buffer description information. The encoded pictures included in the bitstream 214 may include one or more encoded reference pictures and / or one or more other encoded pictures.

  Received symbols (in one or more encoded pictures included in bitstream 214) are entropy decoded by entropy decoding module 268, which results in motion information signal 270 and quantized, scaled and / or transformed. A coefficient 272 is generated.

  Motion information signal 270 may be combined with a portion of reference frame signal 298 from frame memory 278 at motion compensation module 274, thereby generating inter-frame prediction signal 282. Quantized, descaled and / or transformed coefficients 272 may be inverse quantized, scaled and inverse transformed by inverse module 262, thereby producing a decoded residual signal 284. The decoded residual signal 284 can be added to the predicted signal 292 to generate a combined signal 286. The prediction signal 292 may be a signal selected from either the inter-frame prediction signal 282 or the intra-frame prediction signal 290 generated by the intra-frame prediction module 288. In some configurations, this signal selection may be based on the bitstream 214 (eg, controlled by the bitstream 214).

  The intra-frame prediction signal 290 can be predicted from information from the previously decoded combined signal 292 (eg, in the current frame). The combined signal 292 may be further filtered by the deblocking filter 294. The resulting filtered signal 296 may be written to the frame memory 278. The resulting filtered signal 296 may include a decoded picture.

  Frame memory 778 may include a DPB as described herein. The DPB may include one or more decoded pictures that can be held as short-term or long-term reference frames. Frame memory 278 may also include overhead information corresponding to the decoded picture. For example, the frame memory 278 may include a slice header, PPS information, cycle parameters, buffer description information, and the like. One or more of these pieces of information may be signaled from an encoder (eg, encoder 104). Frame memory 278 may provide decoded picture 718.

  An input picture including multiple macroblocks may be divided into one or several slices. If the reference pictures used by the encoder and decoder are the same and deblocking filtering does not use information across slice boundaries, the value of the sample in the area of the picture that the slice represents uses data from other slices Can be properly decrypted. Thus, entropy decoding and macroblock reconstruction for one slice are independent of other slices. In particular, the entropy coding state may be reset at the start of each slice. Other slice data may be marked as unavailable when defining neighborhood availability for both entropy decoding and reconstruction. Slices may be entropy decoded and reconstructed in parallel. Intra prediction and motion vector prediction preferably do not cross slice boundaries. In contrast, deblocking filtering may use information across slice boundaries.

  FIG. 3 shows an exemplary video picture 90 that includes 11 macroblocks in the horizontal direction and 9 macroblocks in the vertical direction (9 exemplary macroblocks are labeled 91-99). . FIG. 3 shows a first slice 89 labeled “Slice # 0”, a second slice 88 labeled “Slice # 1”, and a third slice 87 labeled “Slice # 2”. Three exemplary slices are shown. H. The H.264 / AVC decoder can decode and reconstruct the three slices 87, 88, 89 in parallel. Each slice may be sequentially transmitted in the scanning line order. At the beginning of the decoding / reconstruction process for each slice, entropy decoding 268 is initialized or reset, and macroblocks in other slices are marked as unavailable for both entropy decoding and macroblock reconstruction. Thus, for a macroblock in “slice # 1”, eg, the macroblock labeled 93, the macroblocks in “slice # 0” (eg, the macroblocks labeled 91 and 92) are entropy decoded or It cannot be used for reconstruction. On the other hand, for macroblocks in “slice # 1”, eg, macroblocks labeled 95, other macroblocks in “slice # 1” (eg, macroblocks labeled 93 and 94) are entropy. Can be used for decryption or reconstruction. Thus, entropy decoding and macroblock reconstruction proceed sequentially within a slice. Unless the slice is defined using flexible macroblock ordering (FMO), the macroblocks in the slice are processed in raster scan order.

  Flexible macroblock ordering defines slice groups and changes how a picture is divided into slices. Macroblocks within a slice group are defined by a macroblock-to-slice group map, which is signaled by the contents of the picture parameter set and additional information in the slice header. The macroblock-to-slice group map includes a slice group identification number for each macroblock in the picture. The slice group identification number specifies which slice group the associated macroblock belongs to. Each slice group can be divided into one or more slices, where a slice is a series of macroblocks within the same slice group that are processed in raster scan order within a set of macroblocks of a particular slice group. Entropy decoding and macroblock reconstruction proceed sequentially within a slice group.

  FIG. 4 shows a first slice group 86 indicated as “slice group # 0”, a second slice group 85 indicated as “slice group # 1”, and a first slice group 85 indicated as “slice group # 2”. 3 shows exemplary macroblock assignments of three slice groups 84 to three slice groups. These slice groups 84, 85, 86 are associated with two foreground regions and one background region in the picture 90, respectively.

  A picture may be divided into one or more slices, and if the reference pictures used in the encoder and decoder are the same, the slice will return the value of the sample in the area of the picture that the slice represents It is self-contained in that it can be reconstructed correctly without using data from the slice. All reconstructed macroblocks in the slice are available in the neighborhood definition for reconstruction.

  A slice may be divided into more than one entropy slice, which can correctly entropy decode the area of a picture that the entropy slice represents without using data from other entropy slices, Self-contained. The entropy decoding 268 may be reset at the start of decoding of each entropy slice. Data in other entropy slices may be marked as unavailable when defining neighborhood availability for entropy decoding.

  A device configured to decode a picture obtains or otherwise receives a bitstream that includes a series of pictures including the current picture. The device further obtains a reference picture set (RPS) parameter that can be used to identify other frames that can be used to decode a picture that follows the current picture in the order in which the picture is signaled in the current picture or bitstream.

  The RPS provides identification of a set of reference pictures associated with the current frame. RPS identifies a reference picture before the current picture in decoding order that can be used for inter prediction of the current picture and / or identifies a reference picture after the current picture in decoding order that can be used for inter prediction of the current picture Yes. For example, if the system receives frames 1, 3, 5, 5 uses 3 as a reference, and the encoder uses frame 1 for prediction of frame 7, an RPS of 5 will cause frame 1 to reference frame 5. Even if not used, both frames 3 and 1 may be signaled to be maintained in the frame memory 278. In one embodiment, the RPS of 5 may be [−2−4]. In addition, the frame memory 278 may be referred to as a display picture buffer, or equivalently DPB.

  The RPS describes one or more reference pictures to be retained for at least a limited duration in a decoded picture buffer (DPB) for later use. This RPS identification may be included in the slice header of each picture together with the picture and / or together with the picture group. In addition, a list of RPSs may be sent in a picture parameter set (PPS). The slice header may then point to one of the RPSs transmitted in the PPS in order to signal usage in that slice. For example, the RPS of the picture group may be signaled in the picture parameter set (PPS). Any picture in the DPB that is not part of the RPS of the current frame may be marked as “not used for reference”.

  The DPB can be used to store pictures reconstructed (eg, decoded) at the decoder. These stored pictures can then be used, for example, in inter prediction techniques. In addition, a picture in the DPB may be associated with a picture order count (POC). The POC may be a variable associated with each coded picture and having a value that increases with increasing picture position in output order. In other words, the POC can be used by the decoder to send the pictures in the correct order for display. The POC may also be used for identification of reference pictures during construction of the reference picture list and identification of decoded reference pictures. Furthermore, POC can be used to identify pictures lost during transmission from the encoder to the decoder.

  Referring to FIG. 5, an example of a set 300 of frames supplied from an encoder to a decoder is shown. Each frame only needs to have an associated POC 310. As shown, the POC may be incremented from a negative number to a large positive number. In some embodiments, the POC may only increment from zero to a larger positive number. The POC is typically incremented by 1 for each frame, but one or more POCs may be skipped or otherwise omitted. For example, the POC of the set of frames in the encoder can be 0, 1, 2, 3, 4, 5, etc. For example, the POC of the same set of frames or another set of frames in the encoder may be 0, 1, 2, 4, 5, etc., and POC3 may be skipped or otherwise omitted.

  As the POC becomes sufficiently large, a large number of bits will be required to identify each frame using the POC. The encoder reduces the number of bits used to identify a particular POC by using a selected number of least significant bits (LSBs) of the POC, such as 4 bits, to identify each frame be able to. Since the reference frame used to decode the current frame is often located close in time to the current frame, this identification technique is appropriate, reducing the computational complexity of the system and the overall video bit rate. Reduction. The number of LSBs used to identify a picture may be signaled to the decoder in the bitstream.

  As shown in the figure, when the selected number of POC LSBs is 4, the LSB is 4 bits and the LSB index repeats every 16 values (2 ^ 4). Thus, frame 0 has an LSB with a value of 0, frame 1 has an LSB with a value of 1, ..., frame 14 has an LSB with a value of 14, and frame 15 has 15 LSB with value. However, frame 16 again has an LSB with a value of 0, frame 17 again has an LSB with a value of 1, and frame 20 has an LSB with a value of 4. The LSB identifier (generally also referred to as POC LSB, or equivalently POC LSB), should only have the characteristics LSB = POC% 16, where% is 16 (2 ^ number of least significant bits, here This is the remainder after dividing by 4). Similarly, if the selected number of LSBs for identifying POC is N bits, the LSB identifier only needs to have the characteristics LSB = POC% (2 ^ N), where 2 ^ N is 2 to the Nth power. Rather than including POC in the bitstream to identify the frame, it is preferred that the encoder supply an LSB index (commonly referred to as POC LSB, or equivalently POC LSB) in the bitstream to the decoder.

  The reference frame used for inter prediction of the current frame or a frame after the current frame is either a relative (eg delta) reference (eg using deltaPOC and currentPOC) or an absolute reference (eg using POC). And can be identified by RPS. For example, a frame identified by POC5 310 and signaled to the decoder in the bitstream as LSB5 320 may have an associated RPS 330 of [-5, -2, -1]. The meaning of the RPS value will be described later.

  Referring to FIG. 6 showing a part of FIG. 5, the RPS of [−5, −2, −1] includes the fifth previous frame 320, the second previous frame 321, and the previous previous frame 322. Refers to the containing frame. This RPS further refers to POC values of 0, 3, and 4, respectively, as shown in FIG. RPS typically refers to the difference between the POC value of the current frame and the POC value of the previous frame. For example, an RPS of [-5, -2, -1] for a current frame with a POC value of 5 is a frame with POC values of 5-5 = 0; 5-2 = 3; and 5-1 = 4 Point to. Note that although not shown in the examples herein, the RPS may also include future frames. These future frames will be indicated with a positive delta PCO value in the RPS.

  If the POC values are not consecutive, such as when one or more POC values are skipped or omitted separately in part of the bitstream, the POC value of the current frame and the previous frame, as shown in FIG. May be different from the number of frames output between the previous frame and the current frame. The RPS may be signaled in the bitstream in any suitable manner, such as supplied with a frame or supplied with a set of frames.

  Referring to FIG. 8, another technique for signaling a reference frame is to use an absolute reference, commonly referred to as a long-term picture, in the RPS associated with the frame. Depending on whether the reference frame is signaled using an absolute reference or relative reference, the decoding process such as a motion vector prediction technique may be different. Absolute reference (referred to as LT for convenience) refers to a specific LSB count value associated with a reference frame, such as a previous frame or a subsequent frame. For example, an absolute reference with LT = 3 (LT3) refers to a reference frame with a POC LSB value of 3. Thus, the RPS of [LT3, -5] refers to a reference frame with a POC LSB value of 3 and a reference frame with POC equal to POC minus 5 of the current frame. In FIG. 8, this RPS corresponds to a reference frame 444 with a POC equal to 3 and a reference frame 320 with a POC equal to 0. Typically, LT3 refers to the first frame before the current frame with a POC LSB value equal to 3. In one embodiment, LT3 refers to the first frame prior to the current frame in output order with a POC LSB value of 3. In the second embodiment, LT3 refers to the first frame prior to the current frame in transmission order, with a POC LSB value of 3. Such a system is suitable for many bitstreams, but is not powerful enough to select a frame with an LSB count value of 3, which is different from the previous frame with an LSB count value of 3.

  Referring to FIG. 9, for example, if the encoder is encoding frame 31 (POC = 31) and the system signals the use of a long-term picture with POC LSB = 0 (LT0), then frame 16 (POC = 16) Since this is the previous frame with LSB = 0, this signaling points to frame 16 (POC = 16) (A). However, even if the encoder wants to signal a long-term picture frame 0 having an LSB count value of 0, it cannot be achieved by a scheme that refers to the previous frame in this way. One technique for overcoming this limitation is to increase the number of least significant bits used to signal the long-term frame LSB or POC LSB. Such an increase in the number of least significant bits is possible, but as a result, considerable additional bits are added to the bitstream.

  A more preferred technique in which fewer additional bits are added to the bitstream is to signal a different long-term picture than the previous frame with a corresponding POC LSB value. For example, the system may indicate the RPS of the current frame with an absolute reference as [LT0 | 2]. Here, 0 indicates the POC LSB count value, 2 indicates the frame to be used among the previous frames whose POC LSB count value is equal to 0, and here, the POC LSB value of the previous 0 (for example, FIG. 9 frame 0). If the second reference is not included, the system may default to the previous POC LSB = 0 [LT0] frame (eg, frame 16 in FIG. 9).

  In many cases, the frequency of requests to signal a frame that is not the first previous frame with the corresponding POC LSB value using an absolute reference will be relatively rare. In order to further reduce the overall bit rate indicating the frame to use, while allowing the ability to signal a frame different from the first previous frame with the corresponding POC LSB value using an absolute reference, the system Duplicate techniques can be used. For example, the RPS may be constructed as [LT0, LT0 | 3]. The overlap of LT0 in the same RPS signal signals to the decoder to use a different frame with a POC LSB value of 0, here a POC LSB value of 0 occurring three times before. In general, the desired POC LSB value corresponds to the occurrence of the indicated previous frame, except that a specific POC LSB value may not be included in a cycle of a specific POC LSB value.

  Referring to FIG. 10, the overlap technique can be shown as follows. The RPS includes a long-term picture signal having a POC LSB value (400) (eg, [LT3]). The same RPS includes another signal of a long-term picture having the same POC LSB value (410) (eg, [LT3, LT3]). The same RPS includes another signal of the second long-term picture having the same LSB count value (410) indicating the position of the desired frame (420) [LT3, LT3 | 2].

  Signaling of the desired frame location may be done in any suitable manner. For example, referring to FIG. 11, the position of a desired frame may be a cycle of a POC LSB value several times before the current frame, for example, three cycles before. For example, referring to FIG. 12, the position may be based on the absolute value of the number of frames offset from the current frame. For example, referring to FIG. 13, the position may be based on the POC LSB value several cycles before the first previous frame with the desired POC LSB value. For example, referring to FIG. 14, the position may be based on the absolute value of the number of frames offset with respect to the first previous frame having the desired POC LSB value.

One implementation of such a technique may use the following syntax:

  First_slice_segment_in_pic_flag equal to 1 specifies that the slice segment is the first slice segment of the picture in decoding order. First_slice_segment_in_pic_flag equal to 0 specifies that the slice segment is not the first slice segment of the picture in decoding order.

  no_output_of_prior_pics_flag specifies how a previously decoded picture in the decoded picture buffer is processed after decoding an IDR or BLA picture. When the current picture is a CRA picture, or when the current picture is an IDR or BLA picture that is the first picture of a bitstream, the value of no_output_of_prior_pics_flag does not affect the decoding process. The current picture is an IDR or BLA picture that is not the first picture of the bitstream and pic_width_in_luma_samples or pic_height_in_luma_samples or sps_max_dec_pic_buffering derived from the active sequence parameter set is derived from the value that is derived from the active sequence leading picture set value No_output_of_prior_pic if different from pic_width_in_luma_samples or pic_height_in_luma_samples or sps_max_dec_pic_buffering [HighestTid] Regardless of the actual value of _flag, equal to 1 no_output_of_prior_pics_flag is (should not be) estimated by the decoder is the. Here, HighestTid indicates the maximum time identifier value.

  The slice_pic_parameter_set_id specifies the value of pps_pic_parameter_set of the picture parameter set being used. It is assumed that the value of slice_pic_parameter_set_id is in the range from 0 to 63 including both end values.

  The dependent_slice_segment_flag equal to 1 specifies that the value of the syntax element of each non-existent slice segment header is estimated to be equal to the value of the syntax element of the corresponding slice segment header in the slice header. When dependent_slice_segment_flag does not exist, the value of dependent_slice_segment_flag is estimated to be equal to zero.

  The variable SliceAddrRS is derived as follows. If dependent_slice_segment_flag is equal to 0, SliceAddrRS is set equal to slice_segment_address. Otherwise, SliceAddrRS is set equal to SliceAddrRS of the preceding slice segment containing the coding tree block whose coding tree block address is ctbAddrTStoRS [ctbAddrRStoTS [slice_segment_address] -1].

  The slice_segment_address specifies the address of the first coding tree block of the slice segment in the raster scan of the coding tree block of the picture. The length of the slice_segment_address syntax element is Ceil (Log2 (PicSizeInCtbsY)) bits. The value of slice_segment_address is in the range from 1 to PicSizeInCtbsY-1 including both end values, and the value of slice_segment_address is the value of slice_segment_address of the NAL unit of any other coded slice segment of the same coded picture. Neither shall be equal. When slice_segment_address does not exist, slice_segment_address is estimated to be equal to zero.

  A variable CtbAddrInRS designates an encoding tree block address in an encoding tree block raster scan of a picture, and is set equal to slice_segment_address. The variable CtbAddrInTS specifies the coding tree block address in tile scan and is set equal to CtbAddrRStoTS [CtbAddrInRS]. The variable CuQpDelta specifies the difference between the luminance signal quantization parameter and its predicted value for the coding unit including cu_qp_delta_abs and is set equal to 0.

  slice_reserved_undetermined_flag [i] has reserved semantics and values for future ITU-T | ISO / IEC standards. The decoder shall ignore the presence and value of slice_reserved_undetermined_flag [i].

  The slice_type specifies the coding type of the slice according to the following table.

  When nal_unit_type has a value in the range from 16 to 23 including both end values (RAP picture), slice_type is assumed to be equal to 2.

  When sps_max_dec_pic_buffering [TemporalId] is equal to 0, slice_type is assumed to be equal to 2.

  pic_output_flag affects the decoding picture output and deletion process. When pic_output_flag does not exist, pic_output_flag is estimated to be equal to 1.

  color_plane_id specifies the color plane associated with the current slice RBSP when separate_color_plane_flag is equal to 1. The value of color_plane_id is assumed to be in the range from 0 to 2 including both end values. A color_plane_id equal to 0, 1, and 2 corresponds to the Y, Cb, and Cr planes, respectively.

  pic_order_cnt_lsb specifies the remainder obtained by dividing the picture order count for the current picture by MaxPicOrderCntLsb. The length of the pic_order_cnt_lsb syntax element is log2_max_pic_order_cnt_lsb_minus4 + 4 bits. It is assumed that the value of pic_order_cnt_lsb is in the range from 0 to MaxPicOrderCntLsb-1, including both end values. When pic_order_cnt_lsb is not present, in most cases pic_order_cnt_lsb is estimated to be equal to zero.

  Short_term_ref_pic_set_sps_flag equal to 1 specifies that a short-term reference picture set for the current picture is created using syntax elements in the active sequence parameter set. Short_term_ref_pic_set_sps_flag equal to 0 specifies that a short-term reference picture set for the current picture is created using the syntax element of the short_term_ref_pic_set () syntax structure in the slice header.

  short_term_ref_pic_set_idx specifies an index to the list of short-term reference picture sets specified in the active sequence parameter set used to create the reference picture set for the current picture. The syntax element short_term_ref_pic_set_idx is represented by the Ceil (Log2 (num_short_term_ref_pic_sets)) bit. If short_term_ref_pic_set_idx does not exist, the value of short_term_ref_pic_set_idx is estimated to be equal to zero. It is assumed that the value of short_term_ref_pic_set_idx is in a range from 0 to num_short_term_ref_pic_sets-1, including both end values.

  The variable StRpsIdx is derived as follows: If short_term_ref_pic_set_sps_flag is equal to 1, StRpsIdx is set equal to short_term_ref_pic_set_idx. Otherwise, StRpsIdx is set equal to num_short_term_ref_pic_sets.

  num_long_term_sps specifies the number of candidate long-term reference pictures specified in the active sequence parameter set included in the long-term reference picture set of the current picture. The value of num_long_term_sps is 0 to Min (num_long_term_ref_pics_sps, sps_max_dec_pic_buffering [sps_max_sub_layers_minus1]-NumNegativePixSxPsPs]. If num_long_term_sps does not exist, the value of num_long_term_sps is estimated to be equal to zero.

  num_long_term_pics specifies the number of long-term reference pictures specified in the slice header included in the long-term reference picture set of the current picture. The value of num_long_term_pics is between 0 and sps_max_dec_pic_buffering [sps_max_sub_layers_minus1] -NumNegativePics [StRpsIdx] _NumPosids_sx_sx_Pix_Psx] If not, the value of num_long_term_pics is estimated to be equal to 0.

  lt_idx_sps [i] specifies an index to the list of candidate long-term reference pictures specified in the active sequence parameter set in order to identify the pictures included in the long-term reference picture set of the current picture. The number of bits used to represent lt_idx_sps [i] is equal to Ceil (Log2 (num_long_term_ref_pics_sps)). If not, the value of lt_idx_sps [i] is estimated to be equal to 0. The value of lt_idx_sps [i] is assumed to be within a range from 0 to num_long_term_ref_pics_sps−1 including both end values.

  poc_lsb_lt [i] specifies a remainder value obtained by dividing the picture order count of the i-th long-term reference picture included in the long-term reference picture set of the current picture by MaxPicOrderCntLsb. The length of the poc_lsb_lt [i] syntax element is log2_max_pic_order_cnt_lsb_minus4 + 4 bits.

  Used_by_curr_pic_lt_flag [i] equal to 0 specifies that the i-th long-term reference picture included in the long-term reference picture set of the current picture is not used for reference by the current picture.

  The variables PocLsbLt [i] and UsedByCurrPicLt [i] are derived as follows. If i is less than num_long_term_sps, PocLsbLt [i] is set equal to lt_ref_pic_poc_lsb_sps [lt_idx_sps [i]] and UsedByCurrPicLt [p] is set to used_by_curr_pic_ps Otherwise, PocLsbLt [i] is set equal to poc_lsb_lt [i], and UsedByCurrPicLt [i] is set equal to used_by_curr_pic_lt_flag [i].

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. Delta_poc_msb_present_flag [i] is equal to 1 when there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i].

  delta_poc_msb_cycle_lt [i] is used to determine the value of the most significant bit of the picture order count value of the i-th long-term reference picture included in the long-term reference picture set of the current picture. When delta_poc_msb_cycle_lt [i] does not exist, delta_poc_msb_cycle_lt [i] is estimated to be equal to zero.

The variable DeltaPocMSBCycleLt [i] is derived as follows:

  For a long-term reference picture set, the decoding process can be performed as follows:

  This process is invoked once per picture, after the decoding of the slice header, but before the decoding of any coding unit and before the decoding process for building the reference picture list of the slice. As a result of this process, one or more reference pictures of the DPB may be marked as “not used for reference” or “used for long-term reference”.

  Note that the reference picture set is an absolute description of the reference picture used in the decoding process of the current and future coded pictures. Reference picture set signaling is explicit in the sense that all reference pictures included in the reference picture set are explicitly listed.

  A picture may be marked as "not used for reference", "used for short-term reference", or "used for long-term reference", but only marked as one of these three Is done. By assigning one of these markings to a picture, another of these markings is implicitly deleted when applicable. When a picture is said to be marked as “used for reference”, a picture marked as “used for short-term reference” or “used for long-term reference” (but not both) Collectively.

  When the current picture is the first picture in the bitstream, the DPB is initialized to an empty set of pictures.

  When the current picture is an IDR picture or a BLA picture, all reference pictures (if any) currently in the DPB are marked as “not used for reference”.

  A short-term reference picture is identified by its PicOrderCntVal value. A long-term reference picture is identified by its PicOrderCntVal value or pic_order_cnt_lsb value.

  To derive the reference picture set, five lists of picture order count values are built; NumPocStCurrBefore, NumPocStCurrAfter, NumPocStFoll, NumPocStFoll, NumPocLtCurr, NumPocLtCurr, NumPocLtCurr, and NumPocLtFoll. .

  If the current picture is an IDR picture, PocStCurrBefore, PocStCurrAfter, PocStFoll, PocLtCurr, PocLtCur, and PocLtFall are all set to empty, NumPocStCurrBefore, NumPocStCurBefore, NumPocStCureBefore.

Otherwise, the following applies to the derivation of the five lists of picture order count values and the number of entries.


Here, PicOrderCntVal is a picture order count of the current picture.

  In an alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. Delta_poc_msb_present_flag [i] is equal to 1 when there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i]. If delta_poc_msb_present_flag [i] is set equal to 1 for the current picture based on the above conditions, it has a TemporalId value of 0 from the subsequent pictures in decoding order, and is one of TRAIL_R, TSA_R, STSA_R. It is assumed that delta_poc_msb_present_flag [i] is set to 1 for all pictures including the first picture in decoding order having a certain NAL unit type.

  In yet another embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i].

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. Delta_poc_msb_present_flag [i] is equal to 1 when there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i]. If delta_poc_msb_present_flag [i] is set equal to 1 for the current picture based on the above conditions, a NAL unit type that has a TemporalId value of 0 and is one of TRAIL_R from subsequent pictures in decoding order. It is assumed that delta_poc_msb_present_flag [i] is set to 1 for all pictures including the first picture in the decoding order.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. Delta_poc_msb_present_flag [i] is equal to 1 when there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i]. If delta_poc_msb_present_flag [i] is set equal to 1 for the current picture based on the above-mentioned conditions, it has a TemporalId value of 0 from the subsequent pictures in decoding order, and among TRAIL_R, TSA_R, STSA_R, RADL_R, and RASL_R It is assumed that delta_poc_msb_present_flag [i] is set to 1 for all pictures including the first picture in the decoding order having the NAL unit type that is one of the above.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. Delta_poc_msb_present_flag [i] is equal to 1 when there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i]. If delta_poc_msb_present_flag [i] is set equal to 1 for the current picture based on the above conditions, for all pictures including from the subsequent picture in decoding order to the first picture in decoding order having a TemporalId value of 0 , Delta_poc_msb_present_flag [i] is set to 1.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. Delta_poc_msb_present_flag [i] is equal to 1 when there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i]. If delta_poc_msb_present_flag [i] is set equal to 1 for the current picture based on the above conditions, it has a TemporalId value greater than 0 or TRAIL_N, TSA_N, STSA_N, RADL_N, RASL_N, RSV_VCL_N10, RSV_VCL_N12, RSV_VCL_N It is assumed that delta_poc_msb_present_flag [i] is set to 1 for all pictures that follow in decoding order with a NAL unit type.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. Delta_poc_msb_present_flag [i] is equal to 1 when there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i]. If delta_poc_msb_present_flag [i] is set equal to 1 for the current picture based on the above conditions, it has a time identifier value equal to 0 from the subsequent pictures in decoding order and is used as a reference picture or individually It is assumed that delta_poc_msb_present_flag [i] is set to 1 for all pictures including the first picture in the decoding order that cannot be discarded.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. If there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i], the current picture and the pictures following the current picture in decoding order have a TemporalId value of 0. Delta_poc_msb_present_flag [i] is equal to 1 for all pictures having a NAL unit type that is one of TRAIL_R and including the first picture in the decoding order after the current picture.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. If there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i], the current picture and the pictures following the current picture in decoding order have a TemporalId value of 0. Delta_poc_msb_present_flag [i] is equal to 1 for all pictures having the NAL unit type that is one of TRAIL_R, TSA_R, and STSA_R and including the first picture in the decoding order after the current picture.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. If there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i], the current picture and the pictures following the current picture in decoding order have a TemporalId value of 0. Delta_poc_msb_present_flag [i] is equal to 1 for all pictures having a NAL unit type that is one of TRAIL_R, TSA_R, STSA_R, RADL_R, and RASL_R and including the first picture in the decoding order after the current picture. And

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. When the decoded picture buffer has more than one reference picture in which the remainder obtained by dividing the picture order count by MaxPicOrderCntLsb is equal to PocLsbLt [i], a TemporalId value greater than 0 is obtained from the current picture and the pictures after the current picture in decoding order. Delta_poc_msb_present_flag is equal to delta_poc_msb_present_flag for all pictures having a NAL unit type of TRAIL_N, TSA_N, STSA_N, RADL_N, RASL_N, RSV_VCL_N10, RSV_VCL_N12 or RSV_VCL_N14.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. When there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i], the current picture and the pictures following the current picture in decoding order have a TemporalId value of 0. Delta_poc_msb_present_flag [i] is assumed to be equal to 1 for all pictures including the first picture in the decoding order after the current picture.

  In a further alternative embodiment, the following semantics can be defined for delta_poc_msb_present_flag [i]:

  Delta_poc_msb_present_flag [i] equal to 1 specifies that delta_poc_msb_cycle_lt [i] exists. Delta_poc_msb_present_flag [i] equal to 0 specifies that delta_poc_msb_cycle_lt [i] does not exist. If there is more than one reference picture in the decoded picture buffer with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i], the current picture and the pictures following the current picture in decoding order have a TemporalId value of 0. Delta_poc_msb_present_flag [i] is equal to 1 for all pictures including the first picture in the decoding order after the current picture that can be used as reference pictures or cannot be discarded individually.

  Here, nal_unit_type is defined by the following semantics.

nal_unit_type specifies the type of the RBSP data structure included in the NAL unit as specified in the table y below.

  Here, the following definitions apply:

  Access unit: A set of NAL units that are related to each other according to a specific classification rule, are consecutive in decoding order, and contain exactly one coded picture.

  The access unit may include other NAL units that do not include the slice segment of the encoded picture in addition to the NAL unit of the encoded slice segment of the encoded picture. The decoding of the access unit always results in a decoded picture.

  Associated non-VCL NAL unit: A non-VCL NAL unit in which a particular VCL NAL unit is an associated VCL NAL unit of a non-VCL NAL unit.

  Associated RAP picture: previous RAP picture (if any) in decoding order.

  Associated VCL NAL unit: nal_unit_type is equal to EOS_NUT, EOB_NUT, FD_NUT, or SUFFIX_SEI_NUT, or is in the range of RSV_NVCL45 to RSV_NVCL47, or in the range of UNSPEC48 to UNSPEC63, V NAL unit; for non-VCL NAL units with nal_unit_type equal to other values, the next VCL NAL unit in decoding order.

  Broken link access (BLA) access unit: An access unit in which the coded picture is a BLA picture.

  Broken Link Access (BLA) picture: A RAP picture in which each slice segment has nal_unit_type equal to BLA_W_LP, BLA_W_RADL or BLA_N_LP.

  A BLA picture contains only I slices and may be the first picture of the bitstream in decoding order or may appear later in the bitstream. Each BLA picture starts a new encoded video sequence and has the same effect on the decoding process as an IDR picture. However, the BLA picture includes a syntax element that specifies a non-empty reference picture set. When a BLA picture has nal_unit_type equal to BLA_W_LP, the BLA picture may have an associated RASL picture that may not be output and decoded by the decoder because it may include a reference to a picture that does not exist in the bitstream. When a BLA picture has nal_unit_type equal to BLA_W_LP, the BLA picture may also have an associated RADL picture designated to be decoded. When a BLA picture has nal_unit_type equal to BLA_W_RADL, it does not have an associated RASL picture but may have an associated RADL picture designated to be decoded. When a BLA picture has nal_unit_type equal to BLA_N_LP, it does not have an associated leading picture.

  Clean Random Access (CRA) access unit: An access unit in which the coded picture is a CRA picture.

  Clean Random Access (CRA) picture: A RAP picture in which each slice segment has nal_unit_type equal to CRA_NUT.

  A CRA picture may contain only I slices and may be the first picture of the bitstream in decoding order, or it may appear later in the bitstream. A CRA picture may have an associated RADL or RASL picture. When a CRA picture is the first picture of a bitstream in decoding order, the CRA picture is the first picture of an encoded video sequence in decoding order, and the associated RASL picture is a reference to a picture that does not exist in the bitstream May not be output and cannot be decoded by the decoder.

  Filler data NAL unit: NAL unit whose nal_unit_type is equal to FD_NUT.

  Instantaneous decoding refresh (IDR) access unit: An access unit whose coded picture is an IDR picture.

  Instantaneous decoding refresh (IDR) picture: A RAP picture in which each slice segment has nal_unit_type equal to IDR_W_RADL or IDR_N_LP.

  An IDR picture includes only I slices and may be the first picture of the bitstream in decoding order or may appear later in the bitstream. Each IDR picture is the first picture of the encoded video sequence in decoding order. When an IDR picture has nal_unit_type equal to IDR_W_RADL, the IDR picture may have an associated RADL picture. When an IDR picture has nal_unit_type equal to IDR_N_LP, the IDR picture does not have an associated leading picture. An IDR picture does not have an associated RASL picture.

  Long-term reference picture: A picture marked as “used for long-term reference”.

  Long-term reference picture sets: Two reference picture set lists that may contain long-term reference pictures.

  Network abstraction layer (NAL) unit: A syntax structure that includes a byte that includes an indication of the type of data that follows and an RBSP that is interspersed with emulation prevention bytes as needed.

  Network abstraction layer (NAL) unit stream: A series of NAL units.

  Non-reference picture: A picture marked as “not used for reference”.

  Non-reference pictures include samples that cannot be used for inter prediction in the decoding process of subsequent pictures in decoding order.

  Picture Parameter Set (PPS): A syntax structure that includes syntax elements that apply to the entire coded picture of zero or more defined by the syntax elements included in each slice segment header.

  Prefix SEI NAL unit: SEI NAL unit with nal_unit_type equal to PREFIX_SEI_NUT.

  Random access decodable reading (RADL) access unit: An access unit whose coded picture is a RADL picture.

  Random access decodable leading (RADL) picture: A coded picture in which each slice segment has nal_unit_type equal to RADL_NUT.

  All RADL pictures are leading pictures. The RADL picture is not used as a reference picture for the decoding process of the trailing picture of the same associated RAP picture. If present, all RADL pictures precede all trailing pictures of the same associated RAP picture in decoding order.

  Random access point (RAP) access unit: An access unit whose coded picture is a RAP picture.

  Random access point (RAP) picture: A coded picture in which each slice segment has nal_unit_type in the range of 7 to 12 including both end values.

  A RAP picture includes only an I slice and may be a BLA picture, a CRA picture, or an IDR picture. The first picture of the bitstream must be a RAP picture. If the required parameter set is available when activation is required, the RAP picture and all non-RASL pictures that follow it in decoding order are processed without performing the decoding process of any pictures that precede the RAP picture in decoding order. It can be decoded properly. Pictures that contain only I slices that are not RAP pictures may also be present in the stream.

  Random access skipped leading (RASL) access unit: An access unit whose coded picture is a RASL picture.

  Random Access Skip Reading (RASL) picture: A coded picture in which each slice segment has nal_unit_type equal to RASL_NUT.

  All RASL pictures are leading pictures of related BLA or CRA pictures. When the associated RAP picture is a BLA picture or the first coded picture of a bitstream, the RASL picture may not be output and decoded properly because it may contain references to pictures that are not present in the bitstream . RASL pictures are not used as reference pictures for the decoding process of non-RASL pictures. If present, all RASL pictures precede all trailing pictures of the same associated RAP picture in decoding order.

  Raw byte sequence payload (RBSP): A syntax structure containing an integer number of bytes encapsulated in a NAL unit. The RBSP is empty or has the form of a string of data bits that includes a syntax element followed by an RBSP stop bit and followed by zero or more subsequent bits equal to zero.

  Raw Byte Sequence Payload (RBSP) stop bit: A bit equal to 1 present after a string of data bits in the Raw Byte Sequence Payload (RBSP). By searching for the RBSP stop bit that is the last non-zero bit in the RBSP from the end of the RBSP, the position of the end of the string of data bits in the RBSP can be identified.

  Reference picture: A picture that is a short-term reference picture or a long-term reference picture.

  A reference picture includes samples that can be used for inter prediction in the decoding process of pictures that follow in decoding order.

  Sequence parameter set (SPS): A syntax applied to the entire encoded video sequence of zero or more determined by the content of the syntax element included in the picture parameter set referenced by the syntax element included in each slice segment header. A syntax structure containing tax elements.

  Short-term reference picture: A picture marked as “used for short-term reference”.

  Step-wise temporal sub-layer access (STSA) access unit: An access unit whose coded picture is an STSA picture.

  Staged temporal sublayer access (STSA) picture: A coded picture in which each slice segment has nal_unit_type equal to STSA_R or STSA_N.

  The STSA picture does not use the same TemporalId picture as the STSA picture for inter prediction reference. A picture that follows the STSA picture in the decoding order having the same TemporalId as the STSA picture does not use a picture preceding the STSA picture in the decoding order having the same TemporalId as the STSA picture for inter prediction reference. The STSA picture enables upward switching from a sublayer immediately below the STSA picture to a sublayer including the STSA picture. An STSA picture must have a TemporalId greater than zero.

  Suffix SEI NAL unit: SEI NAL unit with nal_unit_type equal to SUFIX_SEI_NUT.

  Supplemental enhancement information (SEI) NAL unit: NAL unit with nal_unit_type equal to PREFIX_SEI_NUT or SUFFIX_SEI_NUT.

  Temporary sub-layer access (TSA) access unit: An access unit whose coded picture is a TSA picture.

  Temporal sublayer access (TSA) picture: A coded picture in which each slice segment has nal_unit_type equal to TSA_R or TSA_N.

  The TSA picture and the picture following the TSA picture in decoding do not use a TemporalId picture equal to or higher than the TemporalId of the TSA picture for inter prediction reference. The TSA picture enables upward switching from a sublayer immediately below the TSA picture to a sublayer including the TSA picture or any higher sublayer. A TSA picture must have a TemporalId greater than zero.

  Trailing picture: A picture that follows an associated RAP picture in output order.

  Video coding layer (VCL) NAL unit: A set name of a subset of a coded slice segment NAL unit and a NAL unit having a reserved value of nal_unit_type classified as a VCL NAL unit.

  Video parameter set (VPS): Depending on the content of the syntax element included in the sequence parameter set referenced by the syntax element included in the picture parameter set referenced by the syntax element included in each slice segment header A syntax structure that includes syntax elements that are applied to the entire determined zero or more encoded video sequence.

  Here, the time identifier value is defined as follows.

  nuh_temporal_id_plus1-1 specifies the time identifier of the NAL unit. The value of nuh_temporal_id_plus1 is not equal to 0.

  The variable TemporalId is

  It is specified as TemporalId = nuh_temporal_id_plus1-1.

  If nal_unit_type is in the range from 16 to 23 including both end values (encoded slice segment of RAP picture), TemporalId shall be equal to 0; otherwise, nal_unit_type will be TSA_R, TSA_N, STSA_R or When equal to STSA_N, TemporalId shall not be equal to zero.

  The value of TemporalId is the same for all VCL NAL units of the access unit. The TemporalId value of the access unit is the TemporalId value of the VCL NAL unit of the access unit.

  For example, referring to FIG. 15, for picture B, the decoded picture buffer has more than one reference picture with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt [i], so delta_poc_msb_present_flag [i] is equal to 1 Become. And according to the embodiments described herein, delta_poc_msb_present_flag [i] is set equal to 1 for pictures C and D. Since picture D belongs to TemporalId = 0, the pictures following D in decoding order are obtained from the one in which the remainder obtained by dividing the picture order count by MaxPicOrderCntLsb in the decoded picture buffer for those subsequent pictures is equal to PocLsbLt [i] Delta_poc_msb_present_flag [i] need not be set to 1 unless there are many reference pictures.

  The terms and expressions used in the foregoing specification are used as explanatory terms, not as limitations, and the use of such terms and expressions may include features described in conjunction with the drawings or equivalents thereof. It is understood that there is no intent to exclude and that the scope of the present invention is limited only by the following claims.

Claims (1)

A method for decoding a video bitstream comprising:
Receiving a reference picture set parameter from the video bitstream;
Decoding a current picture using inter prediction based on the reference picture set;
Storing the decoded picture referenced for future inter prediction in a decoded picture buffer;
The reference picture set includes at least (a) one or more reference picture identifiers each based on a selected number of least significant bits (LSB) of the picture order count (POC) of a reference picture;
(B) is decoded by using a flag that specifies whether or not there is subsequent data for determining the MSB of the POC of the reference picture, and the subsequent data is: (i) the decoded picture buffer Having more than one reference picture with the remainder of dividing the picture order count by MaxPicOrderCntLsb equal to PocLsbLt, and (ii) having a TemporalId value of 0 after the picture satisfying condition (i) A method present for the picture that satisfies one of the following pictures in decoding order, including up to the first picture in decoding order that is a trailing picture or reference picture of a stream.